Norman Borlaug went from a small farm in Iowa to feeding half the world, thanks to a lifelong interest in tinkering with the genetic design of wheat. He passed away on September 12 from cancer at the ripe age of 95 and the question remains: Is the Green Revolution dead, too?

In 1944 Borlaug, trained as a plant pathologist, left the U.S. for Mexico to fight stem rust, a fungus that infects wheat, at the invitation of the Rockefeller Foundation, among others. He and his colleagues spent the next decade crossing thousands of strains of wheat from across the globe, ultimately developing a high-yielding, disease resistant variety. Unfortunately, it couldn't stand, heavy with grain.

So Borlaug crossed it again with Japanese dwarf wheat to produce a so-called semidwarf wheat, both shorter (and therefore not prone to tipping over with all that extra grain at the tip) as well as disease-resistant and amenable to fertilization. Where the variety was planted, yields soared.

First Mexico, where he did the work, became self-sufficient in grain (in what was dubbed the "Quiet Wheat Revolution"). Then India and Pakistan, where yields doubled. Paired with similar strains developed for rice and other cereals, a "Green Revolution" was evident in the fields of Asia and helped stave off apocalyptic famine predictions.

"There are no miracles in agricultural production," Borlaug said, but as a result of this increase in food production, millions of lives were saved and Borlaug was awarded the Nobel Peace Prize in 1970.

However, the Green Revolution continues to run into an old Malthusian problem: humans are breeding faster than food supplies can keep up. Despite the fact that wheat varieties based on Borlaug's work cover some 80 million hectares of the globe, food riots broke out in 2008, helped in part, to Borlaug's way of thinking, by the drive for biofuels. And, thanks in part to Borlaug's success, agricultural funding has dried up.

The Green Revolution in Asia has also left a conflicted legacy. Leaving aside the social justice concerns surrounding farm consolidation (and therefore the favoring of rich landowners over peasants), it required massive dams like Bhakra or groundwater mining for irrigation water and huge quantities of synthetic fertilizers made from fossil fuels in addition to Borlaug's wheat. Today, India's waters are drying up and some of the water that remains is now poisoned by those same fertilizers.

Africa also proved resistant to Borlaug's revolution. Despite nearly 30 years of work, yields have not risen as much as he and others hoped—largely because many countries lack the capacity for massive irrigation or road infrastructure needed to truck in fertilizer. But in 2007, for the first time since record-keeping began in the 1960s, per capita food production in sub-Saharan Africa rose, led by countries such as Malawi that subsidized fertilizers.

Borlaug, in later years, turned to genetically modified crops as the best hope for a more bountiful future. And rust is now on the move again, with a new breed out of Uganda. Borlaug's battle may never be completely won and his heirs face unprecedented challenges.

As he said in his Nobel Prize acceptance speech in 1970: "It is true that the tide of the battle against hunger has changed for the better…but ebb tide could soon set in, if we become complacent." Has complacency set in?

After all, "civilization as it is known today could not have evolved, nor can it survive, without an adequate food supply,” Borlaug once said. "The first essential component of social justice is adequate food for all mankind.”